Add Tests to Cycle taking too long with Jira Zephyr API

I created a test cycle in Jira using:

POST jirabaseurl/rest/zapi/latest/cycle
data = {
    "clonedCycleId": "",
    "name": "api-test-cycle",
    "description": "Description of my new cycle",
    "projectId": "18903",
    "versionId": "-1", #To assign the new cycle to an unscheduled version
    "build": "",
    "startDate": "",
    "endDate": "",
    "environment": ""
}

Then I tried adding a Zephyr test to the test cycle:

POST /rest/zapi/latest/execution/addTestsToCycle
addTestToCycle = {
    "method": 1,
    "issues":["test-key-name"],
    "versionId": -1, #If you are not going to use any version, set "versionId": -1.
    "cycleId": 1234,
    "projectId": 2345,
    "folderId": -1,
    "assigneeType": None
}

This gave me a response with jobProgressToken as mentioned in the documentation

To fetch status of job, I do a GET

curl -u username:pass https://baseurl/rest/zapi/latest/execution/jobProgress/jobProgressToken ?type=bulk_execution_copy_move_job_progress

Response: {"zipped":false,"summaryMessage":"","totalSteps":1,"errorMessage":"","entityId":"","message":"","completedSteps":0,"timeTaken":"27 min, 38 sec","stepMessage":"","progress":0.0,"id":"jobProgressToken","stepLabel":"","entity":"","stepMessages":[]}

It's been stuck here for more than 30 mins now and nothing seems to happen. I can't even delete the test cycle now as Add Tests to Cycle is in progress.

What did I do wrong? How to finish this job process?